The present invention relates to video signal processing, and more particularly to a method of transmission of wideband chroma signals.
The preferred format for the exchange of standard definition component video signals is described in SMPTE standard RP-259, SMPTE 125M and ITU-R BT.601. These describe the encapsulation of one luminance channel with a bandwidth of 13.5 MHz and two half-bandwidth chroma channels each with a bandwidth of 6.25 MHz onto one 270 Mbit serial data streamxe2x80x94described as a 4:2:2 video signal. Occasionally it is desirable to transmit a full bandwidth video signalxe2x80x94one with 13.5 MHz bandwidth in each of the luminance and two chroma channels. This is referred to as the 4:4:4 format. In the serial domain SMPTE-174 describes a method of transmitting this wide bandwidth signal in one serial data stream. This is commonly called xe2x80x9cSingle Link.xe2x80x9d The disadvantage of this method is that the serial data doubles to 540 Mbit. This is more difficult to implement and has little support from component manufacturers.
SMPTE-175 describes a method of combining the wide bandwidth signal into two serial data streams. This is commonly called xe2x80x9cDual Link.xe2x80x9d This maintains the standard 270 Mbit data rate but doubles the number of components required, as two data streams must be provided.
What is desired is a method of transmitting a full bandwidth chroma signal using the standard 270 Mbit channel.
Accordingly the present invention provides a method of transmission of wideband chroma signals over a standard 270 Mbit serial digital channel. A video signal having a luminance component and two half-bandwidth chrominance components is converted into two wide bandwidth chrominance components by dropping the luminance component and converting the half-bandwidth chrominance components to wide bandwidth chrominance components. A multiplexer, having the wide bandwidth chrominance components as inputs, outputs half of the wide bandwidth chrominance component samples in place of the luminance component and the other half of the wide bandwidth chrominance component samples in place of the two half-bandwidth chrominance components in a standard 4:2:2 video format to produce a full bandwidth chrominance component 0:4:4 format. The 0:4:4 format is passed by standard 4:2:2 components and then demultiplexed at a receiver to recover the wide bandwidth chrominance components.
The objects, advantages and other novel features of the present invention are apparent from the following detailed description when read in conjunction with the appended claims and attached drawing.